Pharmacological sedation is often necessary in mechanical ventilated intubated patient. Since a little time, sevoflurane can be used in the intensive care unit via a specific heat and moister exchanger called the Anesthetic Conserving Device (AnaConDa®, SedanaMedical AB, Uppsala, Sweden) placed between the Y piece of the ventilatory circuit and the endotracheal tube. Sevoflurane is known to have ventilatory interesting effects such as bronchodilatation that can be useful in the treatment of severe asthma. These effects could be of interest in the intensive care ventilated patients. On the other hand, the AnaConDa® device could have negative influence on ventilatory mechanics caused by the increased dead space and the resistance to air flow. This negative effect with worsening of work of breathing (WOB) was demonstrated with classic heat and moister exchanger compared to heated humidifiers in pressure support ventilation (PSV). In this way, we would like to study the mechanical effects of the sevoflurane administered with the AnaConDa® compared to a classic management with a heated humidifier and sedation with intravenous remifentanil in PSV consecutive intensive care patients.